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Finding the Fourth Proportional to 90.60, 135.12 and 79.80

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Solution

The fourth proportional to 90.60, 135.12 and 79.80 is: 119.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.60 : 135.12 = 79.80 : x
  2. Step 2: Convert to fraction form
    90.60/135.12 = 79.80/x
  3. Step 3: Cross multiply
    90.60x = 135.12 × 79.80
  4. Step 4: Simplify right side
    90.60x = 10,782.58
  5. Step 5: Solve for x
    x = 10,782.58/90.60
  6. Step 6: Final answer
    x = 119.01

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.